Blast furnace



Patented May 25, 1926i.

UNITED STATES PATENT FFICE.

JOSHUA K. CLUTTS, 0F DETROIT, MICHIGAN.

BLAST FUR/NACE.

Application led September 125, 1922. Serial No. 590,497.

This invention relates to blast furnaces the pipe 5 connects through branches 5d with and more particularly relates to blast furnaces associated with rotary kilns which latter effect a preliminary partial reduction of the ore.

Among the objects of the invention are utilization of the slag heat and of the hot gases from the rotary kiln for pre-heating the air supply to the furnace and for other purposes; utilization of the draw stacks of the furnace to house air preheating stoves; delivering partially reduced ore in measured quantities from a rotary kiln, or the like, to a blast furnace and a provision for delivering either hot or cold air or a mixture thereof of regulable proportions to the furnace.

In the drawings Figure 1 is a view in elevation showing the complete equipment comprising the invention;

Fig. 1l is a detail view of the charging device; l

Figure 2 is an enlarged cross section on line 2-2 of Figure l;

Figure 3 is a cross section on line 3-3 of Fi ure 2;

ligure 4 is a detail View of a portion of the sectional air heating stove;

Figure 5 is a plan view of the complete equipment with the stacks thereof shown in section.

In these views the reference character 1 designates a blast furnace, 3 a slag car, travcling to and from said furnace, and 4 a slightly inclined rotary kiln driven by any suitable means (not shown) and having its lower or discharge end adjacent the mouth of the furnace. Raw ore is fed to the higher end of the kiln 4 through a chute 5, to which such ore is delivered by any suitable means, as for example the conveyor 5a. A gradual travel of the ore through the kiln toward the furnace 1 results from rotative actuation of the kiln because of the inclination of the latter, and a suiiiciently high temperature is maintained within the kiln to roast and partially reduce the ore during such travel. The heating of the kiln is effected preferably by combustion of fuel introduced, to-

' gether with air under pressure into the lower end of the kiln. Thus in Figure 1, 5b and 5 are pipes connecting with the kiln at its lower end, the former for discharging gas, tar or powdered coal and the latter furnishing air for the combustion of such fuel. Preferably both the hot air pipe 2O and with the cold air pipe 23 so that the temperature under which the air is delivered to the kiln is regulable. For charging t-he furnace, it is preferred-to employ the device shown in Figure 1 and more fully disclosed in applica-nts co-pend ing application, Serial Number 590,496 and filed of even date herewith. This device comprises a chute 6 discharging from the stationary lower end portion 7 of the kiln, and a charging box 8 into which said chute discharges. As is best seen in Fig. 1a, the

p box 8 is mounted upon the platform 8a of a weighing scale, the beam of which is indicated at 8b. 9 is a steam or air engine actuating plungers l() within said box for periodically ejecting the contents of the same. Preferably the to-p cover 11 of the furnace is so connected to the forward plunger 1() as to move in unison therewith. Thus the mout-l1 of the furnace will be uncovered at the same time that the contents of the charging box are ejected into said mouth.

The hot gases from the top of the furnace are delivered to a pipe 12 and are conducted thereby to two adjacent draw stacks 13, discharging into Said stacks respectively through openings 14 and 14. -Within one of said stacks there is disposed a boiler 15 preferably tubular while an air heating stove 16 is arranged within the other stack. Said stove, as is best shown in Figure 2, comprises separable sections through which air to be heated travels tortuously upwardly. The cold air is delivered to the lower end of said stove through branches 17 from a pipe 18 leading from the blowing engine 1.9. From the top of said stove the heated air is taken off by a pipe 20 and carried to an annular pipe 21 surrounding the lower portion of the blast furnace, there being the usual tuyre pipes 22 opening from the annulus 21 into the blast furnace. The relatively high end of the kiln 4 is in communication with the stack 13, wherein the stoves are located, at a level below said stoves, so that the gaseous products of combustion discharging from the kiln are utilized to heat the stove. As a provision for mixing a regulable quantity of cold air with the supply to the furnace, a branch pipe 23 extends from the outlet end of the blowing engine 19 and connects adj acent the furnace with the hot air pipe 20, the pipes 2O and 23 being respectively controlled by suitable valves 24 and 25. The

closed for conseivation of the heat of the slag. 31 indicates flues rising through the masonry base 29 respectively from the chambers 28 and discharging respectively into the draw stacks 13 at the lower ends thereof. At a suitable point above the slag chambers 2S there' is mounted atank 3Q, forming a receptacle for tar or some similar heavy hydrocarbon. 33 is a` discharge pipe leading downwardly from the tank 32 and branching to discharge downwardly within each chamber 28'. 3st is a steam pipe leading from the boiler 15 and having a portion 35 coiled wit-hin the receptacle for heating the contents thereof to liquefy the same. 3G is a pipe leading from the hot aii'supply main 18 and discharging downwardly into the pipe 33 for placing air pressure upon the discharging tar to expedite the flow thereof.

Considering' now the operation of the described apparatus, it will be understood that green or raw ore is continuously delivered to the raised end of the rotary kiln 4, and owing to the rotation of said kiln in conjunction with the inclination thereof, is gradually fed from the upper to the lower end of the kiln, being` subjected during this passage through the kiln to the hot products of combustion rising through the kiln and thus undergoing a pielin'iinary partial reduction. From the lower end of the kiln the ore discharges through the chute G into the charging box S from which it is periodically de.- livered to the mouth of the furnace. The latter is continuously supplied with the necessary blast of air through the system comprising the blowing engine 19, air heating stove 1G, main cold air pipe 18 and-the pipes 2O and 23. The flow through the two last mentioned pipes is so regulated as to maintain for the air such a teiiiperature as will best satisfy the operating conditions of the furnace; The hot products of combustion flowing' through the rotary kiln are delivered to the stacks13 and are thus utilized for pre-heating the air in the stove 1G and also for heating the boiler 15. rIhe hot gases from the blast furnace being delivered to the stacks through the pipe 12 are similarly utilized. As a further source of heat the slag car (or cars) 3 after they are filled are conducted into one or both of the chambers 28 and the molten slag is subject to a discharge of tar or *he like through the pipe 33. lnstantaneous combustion of the tar results owing to the high temperatui'e of the slag and the resulting combustion products are conducted` through the flues 81 to the stacks 13 to contribute to heating of the air stove and boiler.

'lie described installation, owing to the considerable employment for useful purposes of heat units which in the present 7 practice are largely wasted, is adapted to operate with high efiiciency.

rlhe employment of the rotary kiln to effect a preliminary reduction permits the employment of a blastv furnace much shorter than is feasible where the entire process 0f reduction is carried on within the blast fur nace. This shorter type of furnace is' ad* vanta-geous in that, for a given production, a less amount of fuel is required, and also the quality and composition of the iron may be more readily controlled. Thus the described furnace is peculiarly adapted to deliver iron direct' to molds for making cast ings.

lllhat 1 claim as my invention is 1. A draw stack having a base portion formed with a chamber adapted to receive a slag car and with a fiue leading from said chamber to the stack, and means within d stack for utilizing the heat arising iroin slag within said chamber.

2. The combination with a blast furnace, of a draw stack, means for delivering the hot combustion products from the furnace to said stack, a track leading from the furnace into a chamber in the base of said stack, a slag car operating on said track, and means within said stack for utilizing the ing from slag within said chamber.

3. The combination with a blast furnace, of a rotary kiln for effecting a preliminary reduction of the ore delivered to said furheat of said waste gases and that arisnace, one end of said kiln extending into proximity to said furnace, a stack distant from said furnace with which the other end of said kiln communicates, means for supporting combustion in the lower portion of the kiln and means conveying the hot gases 1 from said furnace to said stack.

4. A stack having a vertical partition therein forming` separate chambers for receiving heat transfer appliances, and a meins for admitting combustion products to 1 said stack within each of said chambers below the level of said appliances.

rlflie combination with a blast furnace having a charging opening in its top poi'- tion, of a rotary kiln for effecting a pi'eliininary reduction of the ore delivered to said furnace, and means for delivering a measured charge of ore from the kiln to the furnace.

(. The combination with a blast furnace having a charging opening in its top portion, of a 'rotary kiln extending into proximity to said furnace, and having a discharge provision adjacent the furnace, a receptacle for the discharge from said kiln, and means for intermittently delivering the contents of said receptacle to the charging opening of the furnace.

7. The combination with a blast furnace 10 having a charging opening in its top portion, of a rotary kiln for effecting a preliminary reduction of the ore delivered to said furnace, a receptacle adjacent to said charging opening into which said kiln discharges, and means for Weighing said receptacle with its contents and for delivering; said contents to said charging opening.

In testimony whereof I aiix my signature.

J OSHUA-K. CLUTTS. 

